1. Tools of a Biologist

2. Microscopes Micro= Scope= Small -to view
A microscope is an instrument used to view very small objects.
In biology it is used to view living….
cells and unicellular organisms.

3. Compound Light Microscope
Eyepiece / Ocular lens
X10
Nose
Arm
Revolving lenses
Stage and
Stage clips
Course Adjustment knob:
Moves stage up and down
Fine adjustment knob:
Fine focuses the image for your eyes

4. Medium power objective lens
High power objective
Low power objective lens.
Longest in length
Blue in color
x40
Shortest lens
Red in color X4
Medium in length
Yellow in color
X 10

5. Base Diaphragm: regulates the
amount of light that passes through the stage
Light source
Base

7. There are 3 types of microscopes are used in biology:
1. Compound light microscope
-Compound-
look through 2 lenses at the same time in order to properly magnify the organism.

8. Total magnification: low power: ocular lens x10 low objective x4
x40
medium power:
med objective x10
x100
high power:
high objective x40
x400

9. Compound light microscope:
-light must pass through the
diaphragm and through the
object.
-object must be “thin” or
transparent so the light can
pass through it.

10. Staining
Is a method of adding color to a cell so that the cell and its structures can be seen more clearly through a microscope.

11. Limit of Resolution
The limit of resolution is the point at which you see an item most clearly.
Any magnification above or below that point will results in the object looking blurry.

12. Type 2: Stereoscope
-Used to view the surface of objects which are too large for light to pass through them.
-Uses to lights to illuminate the surface of the object.
-Stereo means
“3 dimensional”
-Provides a 3-D detailed look at the surface of an object.

14. -look through
2 ocular lenses
-magnifies between x10 to x60

15. Type 3: Electron Microscopes
Uses electrons to form an image and NOT light
Has a very high limit of resolution.
-can see items very clearly at any magnification
-can magnify up to 500,000x and still be clear
Object is placed in a vacuum
No air
No oxygen
Organism is DEAD

16. Two types of electron microscopes:
1. T.E.M. ~ Transmission Electron Microscope
Produces a 2-D, black and white image of inside of a cell.

18. 2. S.E.M. ~ Scanning Electron Microscope
Produces a 3-D, black and white image of the surface of an object.

19. Additional tools of a biologist:
Tool used to separate the components of a mixture by their different densities.
Chromatography: